Need help with highlight the current week...

Hi there,

I have a graph like below, please note this is a dynamic grahic and can be changed everyday. I would like to highlight the currect week I am: (I already have several color on the bar, so it's not a good idea to hightlight the entire bar shince this is already a stacked bar)

Any good suggestion and how to do it? Ideal is we could highlight th e curect a-axis week or add a arror or label on the top to show this is the currect month(But the height of the currect bar is not fix and it is dynamic)